Gurl rounds up the best #badHogwartsclasses, including "Advanced Muggle Studies: Analyzing Selfies" (@PotterToday), "Fantastic Beats by Dre and Where to Find Them" (@MarcDWilkinson), and "He's Just Not That Slytherin to You" (@thechrisarmy).

Kate is the author of After the Fall, coming January 24, 2017 from Farrar, Straus and Giroux. A former teacher and grant writer, she now owns a treehouse-building business in the Ozarks and hosts the Badass Ladies You Should Know interview series.